OPTIONAL FIELD TRIP
Complementing the Global Stone Congress experience, a field trip including visits to beautiful and interesting Bahian stone materials has been organized. The field trip will run from April 30th to May 1st and it will be available to a limited number of participants. It will be billed as an item additional to the main conference fee.
April 30th, Monday – 07:00 h – Departure from Hotel Jardim Atlântico (Ilheus)
- Blue granite (sodalite) and marble quarries visits
- Lunch on route (packed lunch)
- Dinner and accommodation in Itapetinga
- Pegmatite and quartzite quarries visits
- Lunch in Itapetinga
- Snack in Ibicaraí
May 1st, Tuesday – 22:45 h – Arrival to Hotel Jardim Atlântico (Ilheus)
Cost: R$ 425 (included transport, accommodationin Itapetingaand food)
Extra cost for accommodation at Hotel Jardim Atlântico, 1st-2nd May: R$218
Minimum number of participants: 15
Maximum number of participants: 25
Book your place by email: email@example.com
It is highly recommended to wear light and comfortable clothes and sports shoes or boots. It is expected temperatures around 30 oC, shinning sun, but it is probable to have short rains too, so a lightweight compact rain gear may be useful. Hats or caps are also welcome, and sunglasses, solar filter and insect repellent.
The organization reserves the right to cancel part or the entire field trip, in case of rain or an insufficient number of participants. In case of total cancellation, participants will be reimbursed.
THE BLUE STONES OF BAHIA
Participants of the GSC 2018, to be held in Ilheus, will have the opportunity of visiting quarries of the rare and globally known Blue Bahia granites. These materials are geologically related to a Neoproterozoic event of alkaline magmatism, that constitutes the denominated Alkaline Province of the South of the State of Bahia.
The most significant intrusive bodies of the Province are located between the cities of Ilheus and Itabuna to the northeast and Itarantim to the southwest, forming the alkaline suites identified as Itabuna, Floresta Azul and Itarantim-Potiraguá. The dominant rocks are syenitic, part of which nepheline bearing and, less commonly, sodalite bearing.
The alkaline rocks ages are estimated between 680 and 740 Ma. Dykes and other smaller intrusive bodies are also correlated with the Neoproterozoic alkaline magmatism, suggesting their emplacement up to about 550 Ma.
The regional host rocks are associated with Archaean and Paleoproterozoic terrains with main submeridian structure, defined as strongly reworked infracrustal belts with supracrustalvolcanosedimentary remnants. NE-SW tectonic lineaments, discordant to the regional structure, apparently conditioned the intraplate event of alkaline magmatism.
Bahia blue granites (sodalite syenites) have been economically exploited for several decades by a small number of companies. As very rare and highly valued materials, production does not involve expressive volumes. Sodalite concentration can be locally so high that it allows its separation and commercialization as a gemstone.
Other Brazilian blue stones, also used as natural stone, include cordierite gneisses, quartzites with dumortierite and blue quartz-bearing granites. Like the sodalite syenites, also the quartzites with dumortierite only occur in the state of Bahia.
Additional information about the regional geology and its alkaline rocks can be found at:
CPRM. Carta Geológica do Brasil ao Milionésimo, folha Salvador (SD.24); texto e mapas. (Geological Chart from Brazil to the Millionth, Folha Salvador (SD.24); text and maps). Rio de Janeiro, 2004. Available in
Peixoto, Adriana Almeida de. Plutonismo Brasiliano da região de Itabuna, Bahia: geologia, petrologia e geoquímica. Org. Dante Severo Giudice, Icalmar Vianna. Salvador: CBPM, 2017. 70 p. (Série Publicações Especiais; 19). Síntese da tese de doutorado da geóloga Adriana Almeida de Peixoto, apresentada na UFBa – Universidade Federal da Bahia, em 2005). Disponível em:
http://www.cbpm.ba.gov.br/modules/conteudo/conteudo.php?conteudo=24. Acessadoem 04/02/2018.